Abstract: Identification structure (1) with a portrait image (3) of a holder, the identification structure having a substrate (8,50), a laser sensitive layer (11,55) and a lens array (12,56) overlying the laser sensitive layer (11,55), the substrate including a printed pattern (9,54), the laser sensitive layer including a laser engraved image pattern (15,15?; 16,16?). The laser engraved image pattern forms a three dimensional portrait image (A,B) of the holder and the printed pattern forms a two-dimensional color pattern (C) of the portrait image of the holder, wherein the two-dimensional color pattern (C) and the three-dimensional portrait image (A,B) are adapted to be observed in a superimposed manner.

Abstract: Disclosed is a security document including an image layer with in a first image area an identification image. The document has in a second image area an authentication image that is composed of a first authentication image that is a positive version of the first image and a second authentication image that is a negative version of the first image. The authentication images can be observed at different angles and form a tilt image. Mutual comparison of the positive and negative tilt images and comparison with the identification image provides improved detection of unauthorized alterations.

Abstract: Identification structure (1) with a portrait image (3) of a holder, the identification structure having a substrate (8, 50), a laser sensitive layer (11, 55) and a lens array (12, 56) overlying the laser sensitive layer (11, 55), the substrate including a printed pattern (9, 54), the laser sensitive layer including a laser engraved image pattern (15, 15?; 16, 16?). The laser engraved image pattern forms a three dimensional portrait image (A, B) of the holder and the printed pattern forms a two-dimensional color pattern (C) of the portrait image of the holder, wherein the two-dimensional color pattern (C) and the three-dimensional portrait image (A, B) are adapted to be observed in a superimposed manner.

Abstract: Disclosed is a security document including an image layer with in a first image area an identification image. The document has in a second image area an authentication image that is composed of a first authentication image that is a positive version of the first image and a second authentication image that is a negative version of the first image. The authentication images can be observed at different angles and form a tilt image. Mutual comparison of the positive and negative tilt images and comparison with the identification image provides improved detection of unauthorized alterations.

Abstract: The invention relates to a method for securing a document including a visual element, carried out by a processing unit comprising processing means, the method comprising generation, from the visual element, of a reference security datum, and storage of the reference security datum, wherein the reference security datum is generated by means of an algorithm configured so as to generate: for any image acquired from the visual element, a security datum whereof the differences relative to the reference security datum are less than a determined threshold, and for any image acquired on a different visual element, a security datum whereof the differences relative to the reference security datum are greater than said threshold.

Abstract: The invention relates to a method for securing a document including a visual element, carried out by a processing unit comprising processing means, the method comprising generation, from the visual element, of a reference security datum, and storage of the reference security datum, wherein the reference security datum is generated by means of an algorithm configured so as to generate: for any image acquired from the visual element, a security datum whereof the differences relative to the reference security datum are less than a determined threshold, and for any image acquired on a different visual element, a security datum whereof the differences relative to the reference security datum are greater than said threshold.